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Question on the TF-100 Test Kit

I have been using the test kit religiously for FC and PH almost daily. I am having trouble with the yellow colors on the FC but the PH is pretty good with the color changes, while the FC is very close between 2, 3, 4 (meaning that my eyesight can not tell the difference). Bright yellow of course.

This morning, about 15 minutes after pouring in 32 ounces of 12.5% liquid chlorine (maybe not enough time for the test to register), and with filter shut off, I also tested for CYA @ 40-50, CC @ O, TA @ 100, etc. If my CC was O and FC was 2.5 based on the extended test directions, does this testing give me a better or more accurate FC test results then the test kit with the 5 drops on each side?

Was the additional chlorine poured in the pool able to register on the test kit in this small amount of time? With the CYA @ 40, my minimum FC is 3 and Target is 5. I will perform an overnight test this evening to determine how much FC I am loosing daily (if any). I would like to bring my levels up at least to 4 ppm daily.

My guess is I was @ 2.5 this morning and after adding 32 ounces of 12.5 that this eventually raised my levels to 4.5 based on the calculator. Am I correct or missing something? Or should I have waited at least one hour with the filter running before I tested my levels again. I want to keep my levels between the recommended ranges daily.

This prompted me to post this after reading a post about the mineralizer system with such low FC levels and cloudy water.

Re: Question on the TF-100 Test Kit

I am a little confused about some of the things you are saying. The tf-100 has 2 chlorine tests: FAS-DPD and OTO.
The FAS-DPD is the one that uses the powder and has a color change from pink to clear. This test is the gold standard.

The other test (OTO) has a color change that you match (yellow). This test is fine for quick sanity check (is my chlorine in the ballpark?) but is nowhere near as accurate as the FAS-DPD.

Did you say that you are adding chlorine with the pump off? That is not recommended.

Re: Question on the TF-100 Test Kit

I would recommend to let the chlorine mix with pump running for 30 mins or so, then test.
Not circulating the chlorine through the water can result in "hot spots" or, areas where the chlorine concentration is higher than others.

The OTO test, the yellow one, is not as accurate at the FAS-DPD. I find some of about 1.5-2 ppm difference when I compare them.
I agree with Svenpup, use teh OTO for a ball park and use the powder test to know the real story.

Re: Question on the TF-100 Test Kit

Originally Posted by svenpup

I am a little confused about some of the things you are saying. The tf-100 has 2 chlorine tests: FAS-DPD and OTO.
The FAS-DPD is the one that uses the powder and has a color change from pink to clear. This test is the gold standard.

Yes, this is the test I was referring to, the one with the powder being more accurate.

The other test (OTO) has a color change that you match (yellow). This test is fine for quick sanity check (is my chlorine in the ballpark?) but is nowhere near as accurate as the FAS-DPD.

I just wanted to clarify that the FAS-DPD test is the more accurate test. This answers my question.

Did you say that you are adding chlorine with the pump off? That is not recommended.

No, I run the pump for about 30 minutes while adding the chlorine.

I have been adding chlorine in the morning with the pump running. The pump runs for about 30 minutes and then is shut off. This morning it was about 15 minutes. Then I shut off the pump and tested the water. I was in a little bit of a hurry this morning. Then the timer goes on @ 12 p.m. and shuts down @ 7 p.m.

Should I purchase extra pins and maybe break down the cycle about 2 hours in the morning and 5 hours in the afternoon? 2X daily? This may be better. This way when I add the liquid chlorine it circulates for about 2 hours. I do not believe the test registered this morning and will find out this evening about 7 p.m.

Re: Question on the TF-100 Test Kit

Originally Posted by Catanzaro

Should I purchase extra pins and maybe break down the cycle about 2 hours in the morning and 5 hours in the afternoon? 2X daily? This may be better. This way when I add the liquid chlorine it circulates for about 2 hours.

This is the way I run mine, but with my Stenner pump the chlorine is being added constantly anytime the pump is running.

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Re: Question on the TF-100 Test Kit

Unfortunately I have an empty frog system now and hopefully the Stenner Pump can fit perfectly in that spot. I am assuming it is some sort of slow drip metered way of adding liquid chlorine. For now I do not mind adding it manually.

Re: Question on the TF-100 Test Kit

Sometimes I can add the chlorine @ night, but my schedule changes a lot. I like to get in a routine and stick with it.

I just went out and tested the levels. This morning I added 32 ounces and in the afternoon I added another 16 ounces of 12.5% liquid chlorine. I performed the FAS-DPD and after the heaping scoop & swirl to mix I added 7 drops before the water turned clear, multiplied by .5 for a FC of 3.5 ppm. It was a hot day today in NJ about 91 with humidity. Tested now as sun is down and clouds have covered everything and raining. Will be dark in a little bit.

Based on the calculator I raised my FC level about 3 ppm today (minus) what I lost during the day possibly meaning that I was low on chlorine before the first 32 ounces (hard to tell).

Should I add more this evening to bring the levels up to 5 ppm? Or should I test in the morning and then add enough to bring me back up to the 5ppm.

Additionally I went out and purchased some pins for the Intermatic Timer so I can have the filter run in the a.m. for about 2 hours (to circulate the new chlorine daily) and then in the afternoon for about 5 hours, therefore giving me 2 run time cycles to match my schedule. It is difficult for me to keep the schedule for the evening.

Re: Question on the TF-100 Test Kit

There is a learning curve as you get a handle on the pulse of your pool. The target is just that, a target. If you find the sun is burning up your FC you can aim just a little higher - you always want to keep above the minimum.

My schedule is a bit funky also and I may be out of town for three to four days to a week or ten days. For that reason I added the Stenner pump. With my usage and tank size I can be goen for a little over three weeks before the tank runs dry.

HERE is the thread that shows my install, including a few photos. I'm not sure if there is a port on your Frog to use as an injection point, but PVC work is easy and you can always cut it out and add a "T" like I did.

The other options are a SWCG and a Liquidator. All three methods add chlorine continuously as your pump runs. Do some searches and decide which is best for you and your pool situation.

TFP Moderator

Trouble Free Pool is a free resource. The people who answer questions are volunteers. If you find the site to be a good resource, please consider making a donation to help support the site. Thanks.